Stabroek News Sunday

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## Hello Boys and Girls!

How was your past week? Have you received the results of your NGFA which you sat on June 26 and 27? I’m sure those results were quite good. What about the NGFA results of your friends? Your time will soon be around.

We have been looking at the solar system for the last few weeks. This week we will begin to look at another topic. We will begin our investigat­ion of Matter. What is matter? Can oil, gold, drink, air, water, bricks or sand be classified as matter?

So, all the items named above can be classified as matter. Everything on this earth that we know of is matter. Do give a few more examples.

Matter can exist in three states. (These states are sometimes referred to as phases or forms.) Can you list these states of matter? Did you list solid, liquid and gas? You’re right. Matter exists as solid, liquid or gas (or a combinatio­n).

## Solids

Get a pebble, a pin, a stopper and a piece of chalk. Touch, move, and twirl each of them in your fingers. Put them all into a bottle and shake it a bit. What do you notice? Do these objects change in any way? These objects are all examples of solids. Name a few more. You can hold solids. Solids have a certain or particular shape. They remain in the same shape wherever we put them. We can pick them up (unless of course, they are too heavy) and move them from place to place. Some solids are hard and some are soft. Some are sticky and some can be stretched. Would you please name a few from each category? That’s good. Did you name elastic or a rubber band for the category of solids that can be stretched? You can perhaps do it like this.

## Liquids

Some liquids are water, oil, vinegar, essence and wine. I’m sure that you can name many more. Pour some coloured water or milk into a container. Now throw it into a container of a completely different shape. What do you observe? You will find that liquids change their shape. Liquids have no special shape or shape of their own. They take the shape of the container that they are in. They first take up the shape of the bottom of the container and the surface is level, regardless of if you twist it.

Liquids take up the same amount of space in one container as in another. Their volume remains the same when poured into a container that is different in shape. We keep a liquid in a solid to stop it from flowing away. Look at some liquids.

## Gases

When a liquid is still its surface is level.

The air that we inhale and exhale is a mixture of gases. These gases are invisible. Oxygen, carbon dioxide, hydrogen and nitrogen are all gases. Can you name a few more? I’m sure that you can.

Blow some air into a balloon so that it is well inflated. Feel it. You can feel the air in the balloon. Gases can take any shape and have no special size.

Open your perfume bottle or a bottle of methylated spirits. Do you smell something? What do you think it is? Gases may spread out in all directions. Gases spread out to fill all the space they can. Gases can indeed increase their volume to fill all the space that is available.

For you to do

1. Pour different liquids to see which liquids flow quickly and which flow slowly 2. Find out the names of gases in the air.

3. Complete this table by putting constant or changing

4. 5. Name the solids and liquids that you used for the entire day.

Let us find out about water and what it can do when things are mixed with it.

Let’s find out !

Do you help in the kitchen? Do you make cold drinks or hot beverages? Think about how you actually did it. What materials did you collect? What did you actually do?

We’re going to do some work in the kitchen now. Get a glass of water, some sugar, salt, a teaspoonfu­l of cooking oil and a spoon.

No, stir about one teaspoonfu­l of sugar into the glass of water. Observe. Taste the mixture. What have you found? Document your observatio­ns.

Do the same with the salt and the oil.

Did you find the sugar as well as the salt mixed in with the water? When this happens we say that the sugar or salt dissolved in the water. The sugar and the salt are called solutes. The water in which each was dissolved is called the solvent. The salt (or sugar) and the water mixed together is called the solution.

SALT + WATER (Solute) + (Solvent)

SUGAR + WATER (Solute) + (Solvent)

Many solids, liquids and gases can dissolve in water. When you dissolve a solid (or liquid or gas), it doesn’t disappear- it’s still there.

When you tasted the water in which the sugar was dissolved, didn’t you taste the sugar and the water at the same time?

Materials that dissolve in water are

SALT WATER (Solution)

SUGAR WATER (Solution)

water soluble.

Classify the items in this list as soluble or insoluble: sugar, nails, buttons, salt, sand, oil, milk, instant coffee. (Do add to this list.)

Name at least two solutes. Which solutes is referred to as the universal solute? Is there a limit to how much of the solute can dissolve? Let’s find out. Pour just a bit of water into a glass (about ¼ of the glass). Now stir in a teaspoon of sugar. What happens? Stir in another teaspoonfu­l, and another, and another. What happens?

Stirring helps to further dissolve solutes, however there comes a time when no more of the solute will dissolve. When that happens we say that that solution is saturated.

How can we get more of the solute to dissolve? You can discuss this with someone else. Did you come up with: